Circuit breaker resetting and closing mechanism



April 1968 J. c. BRUMFIELD ETAL 3,377,574

CIRCUIT BREAKER RESETTING AND CLOSING MECHANISM Filed Oct. 19, 1966 3Sheets-$heet 1 JOHN C. B/Fz/MF/HO BY 09/921155 7T HOE/AG April 1968' J.c. BRUMF'IELD ETAL' 3 Sheets-Sheet 2 Filed 001;.

INVENTORS Jd/f V c. JEUMF/Edfl By 099924159 7. fla /A15 A ril 9, 1968 J.c. BRUMFIELD ETAL 3, 4

CIRCUIT BREAKER RESETTING AND CLOSING MECHANISM Filed Oct. 19, 1966United States Patent 3 377,574 CIRCUIT BREAKER RESETTING AND CLOSINGMECHANISM John C. Brumfield, Philadelphia, and Charles T.

Robins, Swarthmore, Pa., assignors to I-T-E Circuit Breaker Company,Philadelphia, Pa., a corporation of Pennsylvania Filed Oct. 19, 1966,Ser. No. 587,709 9 Claims. (Cl. 335-27) ABSTRACT OF THE DISCLOSURE andtripped posi- This invention relates to circuit breakers, and moreparticularly relates to mechanism for effecting automatic movement ofthe movable contact of a circuit breaker from its tripped to its on orclosed circuit position in response to the operating handle of suchcircuit breaker being moved from its tripped to its on position.

In recent years there has been considerable effort expended in theelectrical industry to reduce the size of circuit protective equipment.For example, in the area of small air circuit breakers of the type withwhich the instant inventiop is intended to cooperate, the industry hasseen acceptance of one-half inch wide circuit breakers as a substitutefor the long accepted one inch breaker. Further evidence of the presentemphasis on reduction in size and simplicity in design is evidenced byUnited States patent application Ser. No. 632,045, filed Apr. 19, 1967,entitled, Circuit Breaker Mechanism Mounting Plate Assembly, to Carl E.Gryctko, and assigned to the assignee of the instant invention, wherethere has been described in great detail a novel circuit breaker whichhas achieved utmost simplicity in design and maximum reduction inoverall size.

Simultaneously with the development of smaller and more simplifiedcircuit breakers, and related thereto, en-

gineers have re-examined the operating characteristics of 'stantaneousfault current trips the latching mechanism whereby an overcenter springoperated mechanism snaps the circuit breaker movable contact to its opencircuit po sition. The breaker is now in its tripped position.

After the fault has been cleared and it is necessary to re-establish thecircuit being protected, the following steps are normally required.First, the operating handle of the circuit breaker is moved from itstripped position (that is, the position the handle occupies with thecircuit breaker contact open and the latching mechanism tripped) inafirst direction to a reset position in which the latching mechanism iscocked for subsequent operation. In the reset position, the movablecontact of the circuit breaker remains open, and hence the resetposition is commonly called the off position. Finally, the operatinghandle is moved in the opposite direction from the reset position backto the on position. It is obvious that the two-step operation requiredto convert a circuit breaker from its tripped position to its onposition is diametrically opposed to the basic concept of simplicitywhich today is of primary importance in the circuit breaker field.

. The instant invention addresses itself to both problems outlinedabove. That is, with conscientious effort it has been specificallydesigned to cooperate with the circuit breaker operating mechanism ofthe aforementioned application Ser. No. 632,045, although in no wayintended to be limited to such environment; while at the same time itsimplifies circuit breaker operation, by providing that in one singlemovement of the operating handle thereof from the tripped to the onposition, the movable contact of the circuit breaker will experiencecomplete, automatic, and continuous movement from its tripped positionthrough the off position and to the on position.

Specifically, and as explained in greater detail in said aforementionedpatent application Ser. No. 632,045, a circuit breaker is provided witha common, relatively flat mounting plate upon which all parts of thecircuit breaker mechanism are ultimately secured and about points onwhich various movable parts of the circuit breaker mechanism may rotate.The breaker includes a stationary contact and a movable contactrotatable about a pivot point provided on a cradle member pivotallysecured to the aforementioned mounting plate. A handle is connected tothe movable contact by means of an overcenter operating spring, with thelatch of the tripping mechanism of the breaker maintaining the cradle inits latched position whenever the breaker is in the on or off condition.

Upon the occurrence of a predetermined fault, the tripping mechanismpermits the release of the cradle whereby the overcenter spring rotatesboth the cradle and the movable contact to open the crcuit beingprotected.

To perform the automatic reclosing of the circuit breaker contacts upon.the movement of the operating handle from its tripped to its onposition, there is provided automatic relatching means in the form of alinkage assembly which cooperates with the operating handle, the cradle,and the common mounting plate of the circuit breaker to perform threeprimary functions. First, the automatic relatching means is so arrangedas to define an intermediate or off position for the circuit breakeroperating handle when such handle is manually rotated between its on andoff position to close and open, respectively, the circuit breakercontacts while the cradle is latched. Second, upon the occurrence of afault as detected by the circuit breaker tripping mechanism, theautomatic relatching means is so arranged as to permit the circuitbreaker operating handle to rotate past its off to its tripped positionduring which'time, of course, the circuit breaker movable contact isexperiencing further movement to its tripped position, beyond its 01fposition, to assure current interruption. Third, in response to a singlecontinuous movement of the circuit breaker operating handle from itstripped back to its on position, the automatic relatching means is soarranged as to (1) automatically relatch the cradle of the breaker and(2) return the circuit breaker movable contact to its engaged or onposition. i

It is to be understood that, although the instant invention has been andwill be further described with respect to the particular operatingmechanism of the novel circuit breaker shown and claimed in applicationSer. No. 632,- 045, it is in no way limited to use in such circuitbreaker but rather applicable to any type of circuit breaker mechanismwhich includes both an operating handle and a latchable cradle.

Accordingly, it is an object of the instant invention t provideautomatic relatching means for use in a circuit breaker which achievesboth the latching of the cradle thereof and the movement of the movablecontact thereof between its tripped and on position in response to asingle continuous movement of the operating handle thereof between itstripped and on position.

Another object of the instant invention is to provide such automaticrelatching means which is particularly adapted to cooperate with circuitbreakers especially designed from the viewpoint of reduction in size andutmost simplicity in operation.

Another object of the instant invention is to provide such automaticrelatching means comprised of a linkage assembly of a minimal number ofparts so arranged as to perform a multiplicity of functions.

Still another object of the instant invention is to provide suchautomatic relatching means which defines an oif position for a circuitbreaker operating handle; permits such operating handle to pass said offposition and reach a tripped position in response to the detection of afault by the tripping mechanism of such breaker; and causes theoperating mechanism of such breaker to be automatically relatched andthe movable contact of the breaker to experience movement from itstripped to its on position in response to a single continuous move-mentof the operating handle from its tripped to its on position.

Other objects and a fuller understanding of the instant invention may behad by referring to the following description and drawings, in which:

FIGURE 1 is an exploded perspective view of internal parts of a circuitbreaker constructed in accordance with the teachings of saidaforementioned patent application Ser. No. 632,045, and including theautomatic relatching means of the instant invention;

FIGURE 2 is a plan view, with the cover removed, of the circuit breakerof FIGURE 1, with the operating mechanism thereof occupying the onposition;

FIGURE 3 is a partial view of the circuit breaker of FIGURE 2, with theparts thereof occupying the oif position; and

FIGURE 4 is a view similar to FIGURE 3, but showing the circuit breakerin the tripped position.

Referring to FIGURE 1, there is shown the internal mechanism of acircuit breaker constructed in accordance with the principles of theaforementioned patent application Ser. No. 632,045, which mechanismincludes the automatic relatching apparatus 12 of the instant invention.It is re-emphasized that although the automatic relatching apparatus 12will be specifically described with respect to the internal mechanism 10of said aforementioned pending application, it is to be understood thatsuch disclosure is intended in no way to limit the application of theinstant invention, since the instant invention is equally applicable toany circuit breaker mechanism which includes both an operating handleand a rotating cradle as part of its operation.

Similarly, it is to be understood that although the instant inventionwill be described with respect to a circuit breaker for the protectionof a single phase of current, the instant invention could beappropriately modified (for example, by tying together three linkageassemblies to operate simultaneously) to operate in a circuit breakerfor the protection of more than one phase.

The circuit breaker mechanism 10 includes a common plate 14 integrallyprovided with the following parts: an upstanding cradle-pivoting tab 16;an upstanding relatching-pivoting tab 18; an upstanding trippermechanismpivoting tab 20; and an upstanding spring-retaining tab 22. Inaddition the plate 14 includes an elongated slot 24; a generallycentrally located operating handle-pivoting aperture 26; and an arcuateslot 28 which receives an upstanding tab portion of the operating handle30, as hereinafter described.

The operating handle 30 includes an upstanding knob receiving tab 32 atone end thereof, and a pair of upstanding tabs 34 and 36 at the oppositeend thereof. Tab 34 is provided with an open-ended slot 38 which fitsover a portion 40 of the mounting plate defining the aperture 26 wherebythe operating handle 30 may experience rotation in a plane parallel tothe plane of the mounting plate 14 about the point 40. The second tab 36of the operating handle 30 is freely received within the arcuate slot 28and extends forward of the mounting plate 14 when the operating handle30 is placed behind the mounting plate 14 with the open-ended slot 38,ridingon the point 40. Biasing means in the form of spring 42 is securedat one end thereof to the tab 36 and at the opposite end thereof to theupstanding spring-retaining tab 22 so as to constantly bias theoperating handle 30 in a counterclockwise direction in FIGURE 1 aboutthe pivot defined by the slot 38 and point 40.

A cradle 44 includes a bifurcated end 46, the two arms 48 and 50 ofwhich include aligned apertures 52 which receive the cradle pivoting tab16 of the mounting plate 14. The opposite end of the cradle 44 includesan upstanding latch tip 54 which cooperates with the latch 56 of thetripping mechanism 80, as will be described in further detail.

. Intermediate the ends of the cradle 44 is an over-turned tab 58 whichcooperates with an open-ended slot 60 provided at one end of a movablecontact arm 62 to permit rotation of the movable contact arm 62 aboutpoint 64 on the cradle 44 when the movable contact arm 62 is inser'tedup and under the over-turned tab 58.

The opposite end of the movable contact arm 62 integrally carries agenerally S-shaped spring-retaining portion 66 and also carries agenerally L-shaped portion 68 which carries the movable contact pad'70thereon. Disposed opposite to the movable contact pad 70 is a stationarycontact pad 76 secured to the stab 78 of the breaker.

A main operating spring 72 is secured at one end thereof to the S-shapedspring-retaining portion 66 and at the opposite end thereof is securedto a spring-retaining portion 74 which is an integral portion of theupstanding knob-retaining portion 32 of the operating handle 30.

Tripping mechanism generally designated at 80 includes a bimetallicelement 82 and a magnetic element 84 to which is secured the latch 56.

In response to predetermined overload or instantaneous fault conditions,tripper mechanism 80 will rotate clockwise in FIGURE 1 to move the latch56 out'of engagement with the latch tip 54 of cradle 44 to permit themain operating spring 72 to rotate contact arm 62 clockwise and therebyinterrupt current flow through'the path defined by stab 78, stationarycontact pad 76, movable contact pad 70, conductive braid 86, bimetallicelement 82, conductive braid 88, and stab The automatic relatching means12 of the instant invention includes first and second members 92 and 94,respectively, which are joined as by a pin 96 for rotation relative toone another. The first member 92 includes a centrally located aperture98 which is received and carried by the upstanding pivot point 18 onmounting plate 14 to permit rotation of the linkage assembly relative tothe plate 14. The first member 92 also includes a pair of actuatingsurfaces 100 and 102, for purposes to be further explained, while thesecond member 94 terminates in an upstanding actuating surface 104 whichterminates in a re-arwardly disposed portion 106 whichlies in a planebehind the planar surface of the second member 94 so that it may ridebehind the mounting plate 14 with the upstanding actuating surface 104projecting through the elongated slot 24 and beyond the front surface ofthe plate 14. It may be noted that actuating surface 102 of member 92retains one end of a biasing spring 103, the opposite end of which issecured to a hook-like projection 105 provided on the tripping mechanism80 to constantly bias the first member 92 of the automatic relatchingmechanism in a counterclockwise direction about the pivot point 18. I

Referring to FIGURE 2, there is shown the manner in which the circuitbreaker operating mechanism cooperates within a circuit breaker casinggenerally indicated at 110. The casing 110- normally includes a cover,not shown, which when removed reveals the mechanism housing cavity 112.The casing walls include appropriately located passageways for stabs 78and 90; a passageway 114 to permit the exit of gases generated duringcircuit interruption in the manner taught by United States patentapplication Ser. No. 568,500, filed July 28, 1966, entitled VentedMounting Block for Circuit Breaker, in in the name of Carl E. Gryctko,assigned to the assignee of the instant invention, and now issued as US.Patent 3,328,553 on June 27, 1967; and a passageway 115 providedth-rough the outer casing wall to house an adjusting screw 117 which isscrew-threaded through an upstanding tab 119 provided on the mountingplate 14 to vary the position of the bimetallic element 82 and hence theentire tripping mechanism 80- relative to the latch tip,

54 of cradle 44. (Note that the tripping assembly 80 is constantlybiased in a counterclockwise direction in FIGURE 2 by the biasing spring103 secured between the hook-like projection 105 on the trippingmechanism and the actuating surface 102 provided on the first member 92of the automatic relatching mechanism.) The external casing wall is alsoremoved at 116 through which an operating knob 118 may 'be secured tothe operating handle 30 of the internal mechanism in a manner to befurther described. The upper arcuate opening 116 is defined at oppositeends thereof by casing wall projections 120 and 122.

In the interior cavity 112 and upstanding from the rear wall 124 of thecasing 110 there is provided an internally generally U-shaped projection126 which houses the bifurcated end 46 of the cradle 44 which in turn ispivoted upon the tab 16 of the mounting plate 14.

The operating knob 118 is actually an integral portion of a one-piecearc-like member 124a which is guided for movement within the interior112 of the casing 110 by the internal surfaces of the casing walls aswell as the upstanding projection 126. The arc-like member 124a has acutout notch 127 which receives the upstanding tab 32 of the operatinghandle 30 whereby rotation of the knob 118 between limits defined bywall projections 120 and 122 will similarly rotate the operating handle30 v In FIGURE 2 the circuit breaker is in the on position, that is,with the contact pads 70 and 72 completing a circuit path through thestab -78, contact pads 70, 72, the conductive braid 86, the bimetallicelement 82, the conductive braid 88 and through the stab 90. In the oncondition, the latch 56- of the tripping mechanism 80 is in a blockingrelationship with respect to the latch tip 54 of cradle 44, with theoperating spring 72 biasing the movable contact arm 62 in acounterclockwise direction about point 64 on cradle 44 to maintain themovable contact pad 70 in firm electrical contact with the stationarypad 76.

It will further be observed that in the on position, biasing spring 103attempts to establish as short a distance as possible between theprojection 105 on the tripping mechanism 80 and-the actuating surface102 on the first member 92 of the automatic relatching assembly wherebythe planar actuating surface 100 of member 92 is necessarily sopositioned as to be in the path of movement of an upstanding tab 128(which cannot be seen in FIGURE 1) provided on the operating handle 30The function of this last mentioned upstanding tab 128 on the operatinghandle 30 may best be understood by referring to FIGURE 3 wherein theoperating handle 30 has been manually moved from its on position to anoff position intermediate the projections 120 and 122, and during whichtime the operating spring 72 has passed over point 64 on the cradle 44to rotate the movable contact arm 62 from its on position to its offposition. Note that since the opening of the circuit breaker was bymanual operation and not in response to the occurrence of a fault, thecircuit breaker is in an off position rather thanthe tripped position,with the cradle 44 still being latched by the cooperation of latch 56and latch tip 54.

As can be most clearly seen in FIGURE 3, the operating handle 30 ismaintained in the off position by the cooperation of actuating surfaces100 and 102 of member 92 with the upstanding tab 128 and the cradle 44,respectively. Specifically, as the operating handle 30 is rotated bymeans of the knob 118 counterclockwise in FIGURE 3, the tab 128 on theoperating handle 30 engages the actuating surface 100' of member 92.However, with the cradle 44 latched, further counterclockwise rotationof the member 92 of the automatic relatching assembly 12 is prevented bythe engagement of the upstanding actuating surface 102 thereon with thecradle 44.

Turning now to FIGURE 4, it will be assumed that a time-delayed orinstantaneous fault current has been detected by the tripping mechanismso as to rotate latch 56 from it blocking position with respect to thelatch tip 54 of cradle 44. At this time the operating spring 72 rotatesmovable contact arm 62 and necessarily the cradle 44 in a clockwisedirection to the tripped position shown in FIGURE 4, whereby there iseven a greater separation between contact pads 70 and .76 therebyassuring extinguishment of any arc drawn therebetween. Simultaneouslyand with the aid of biasing spring 42, the operating handle 30 isurgedthrough its off position in FIGURE 3 to its tripped position in FIGURE4, it being noted that the upstanding tab 128 thereon is now free torotate member 92 counterclockwise since the actuating surface 102thereof is no longer restrained by the cradle 44 as it was in FIGURE 3.It is to be noted that while member 92 -is being rotatedcounter-clockwise, biasing spring 103 is put under tension whereby oncethe operating handle 30 has reached its tripped position and theupstanding tab 128 thereof is no longer in engagement with the actuatingsurface under it (this instant in time being shown in phantom at inFIGURE 4), the member 92 will be rotated clockwise back to the initialposition it occupied in FIGURE 2.

To convert the breaker from the tripped condition shown in FIGURE 4 backto the on position shown in FIGURE 2, the operator merely grasps theknob 118 and rotates it (and the operating handle 30) from its positionin abutment with the wall projection 120 to its other extreme positiondefined by the wall projection 122. In so doing, the upstandingprojection 128 on the operating handle 30 engages the actuating surface100 of member 92 once again such that the member 92 rotates clockwise inFIGURE 4 and the second member 94 with the actuating surface 104 aremoved toward the left in FIG- URE 4, the movement of the actuatingsurface 104 being guided by the elongated slot 24 into contact with thecradle 44.

As this motion continues, the upstanding actuating surface 104 causesthe cradle 44 to be rotated counterclockwise in FIGURE 4 until the latchtip 54 passes beneath the latch 56 (which has been urgedcounterclockwise in FIGURE 4 by the biasing spring 103) at which timethe cradle 44 will occupy the latched position shown in FIGURE 3.

Finally, when the operating handle 30 passes over center point 64, theoperating spring 72 will snap the movable contact arm 62counterclockwise in FIGURE 4 until it reaches the on position shown inFIGURE 2. Thus the circuit breaker has been converted from trip to onposition with one continuous mot-ion of the operating handle 30.

It should be noted that once the upstanding tab 128 of operating handle30 is free of the actuating surface designated at 100" in FIGURE 4, thebiasing spring 103 will again return the member 92 to the position shownin solid in FIGURE 4 (corresponding to FIGURE 2), whereby the automaticrelatching mechanism will be in condition to function properly foreither the next tripping operation or manual movement from the on to offpositions.

Thus there has been described automatic relatching mechanismspecifically adapted for cooperation with the novel operating mechanismof a circuit breaker designed to reduce size and simplify operationwhich makes possible the conversion of a circuit breaker from itstripped to its on condition with one single continuous movement of theoperating handle of such breaker from its tripped to its on position.

Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now be apparent tothose skilled in the art. Therefore, this invention is to be limited,not by the specific disclosure herein, but only by the appending claims.

We claim:

1. A circuit breaker comprising:

a first contact; a

a second contact movable between a first position engaging said firstcontact and a second position disengaged from said first contact; an armupon which said second contact is mounted;

operating means connected to said armmovable between a latched andtripped position for moving said second contact from its first to itssecond position in response to predetermined conditions;

an operating handle movable between trip and on positions for movingsaid second contact from its second position back to its first positionafter said second contact has been moved to its second .position inresponse to movement of said operating means from its latched to trippedposition;

with said operating means in said latched position said operating handlealso being operable to an off position wherein said contacts aredisengaged;

said off position for said operating handle located intermediate said onand said tr-ip positions; and automatic relatching means engageable bysaid operating handle and said operating means for automatically movingsaid operating means to its latched po sition in response to movement ofsaid operating handle from its tripped position toward its on positionwhereby movement of said operating handle will automatically move saidoperating means to its latched position and thereafter automaticallymove said second contact from its second position to its first position.

2. The circuit breaker of claim :1, wherein said operating meansincludes a cradle member rotatable about one end thereof between itslatched and tripper positions; and said automatic relatching meansincludes linkage means having first and second actuating surfaces, saidfirst actuating surface being movable between a first and secondposition in response to movement of said operating handle from its triptoward its on position, said second actuating surface coactingwith saidcradle to rotate said cradle from its tripped to its latched position inresponse to movement of said first actuating surface of said linkagemeans to its second position by said operating handle as it moves towardits on position,

3. The circuit breaker of claim 2, wherein said operating handle isautomatically moved from its on to its trip position in response tomovement of said second contact to its second position; and said firstactuating surface of said linkage means is obstructively positioned inthe path of movement of said operating handle as it moves from its on toits trip position in response to movement of said second contact to itssecond position; and wherein said first actuating surface of saidlinkage means is momentarily moved to a third position by said operatinghandle as said operating handle moves from its on to its trip position;and further including biasing means for returning said first actuatingsurface of said linkage means from its third to its first position aftersaid operating handle passes said first actuating surface of saidlinkage means.

4. The circuit breaker of claim 3, wherein movement of said operatinghandle from its on to its off position causes said second contact to bemoved from its first position to a third position which is intermediatesaid first and second positions of said second contact.

5. The circuit breaker of claim 4, wherein said linkage means includes athird actuating surface which coacts with said cradle to maintain saidfirst actuating surface obstructively positioned in the path of movementof said operating handle to prevent said operating handle from beingmoved to its trip position whenever said cradle is in its latchposition.

6. The circuit breaker of claim 5, and further including a plate member,said linkage means comprising first and second members pivotally linkedto one another, said first member being pivotally mounted on said plateand having said first and third actuating surfaces thereon, said secondmember having said second actuating surface thereon.

7. The circuit breaker of claim 6, and further including trippingmechanism for detecting predetermined fault conditions, said biasingmeans being secured at one end to said tripping mechanism and at itsother end to said third actuating surface.

8. The circuit breaker of claim 6, wherein said plate member has anelongated slot which intersects the path of movement of said cradle, andsaid second actuating surface comprises an upstanding surface which isguided for movement in said elongated slot to rotate said cradle aboutits said one end from its tripped to its latched position in response tomovement of said first actuating surface of said first member from itsfirst to its second position by said operating handle.

9. The circuit breaker of claim 3 further including a second biasingmeans connected with said operating handle for continuously biasing thesame towards said trip position.

References Cited UNITED STATES PATENTS BERNARD A. GILHEANY, PrimaryExaminer.

H. BROOME, Assistant Examiner.

